The invention relates to a stapling head operable during a working stroke to staple piled sheets of paper using wire staples. The stapling head includes a frame, and a staple holder guided in the frame that is displaceable in a working direction essentially perpendicular to the sheets of paper. A staple driver is guided on the staple holder, and is displaceable in the working direction. Driving means are provided for moving the staple holder and the staple driver in the working direction during a first phase of the working stroke, so that the staple holder is moved onto the piled sheets, and is stopped at the piled sheets at an end of the first phase. The driving means move the staple driver further in the working direction to drive a wire staple out of the staple holder and into the piled sheets during a second phase of the working stroke. The driving means move the staple driver and the staple holder back into their initial positions during an idle stroke.
DE 3640529 A1 discloses a stapling head of this type. To drive a staple driver, the known stapling head has a crank and lever mechanism. To drive a staple holder, a crank and lever mechanism is provided with an additional superimposed transmission device. The purpose of this complicated drive is for the legs of a wire staple to be driven only slightly out of its guide in the staple holder before the staple holder comes down on the material to be stapled. The staple legs, at the start of the driving into the material to be stapled, are thereby guided over a large part of their length in the staple holder; this is intended to avoid distortion of the wire staple.
A disadvantage of the known stapling head is the complicated construction of the drive. A further disadvantage is that the staple holder comes down only momentarily on the material to be stapled and is lifted again directly afterwards so that the legs of the wire staple are only guided momentarily over their entire length when being pressed into the material to be stapled.